Actually anything (links, explanations, etc) that explains or details FFT as it relates to Pd would be great... the example patches are a bit cryptic, or sometimes jump a bit too quickly, at least for me.  I want to eventually generate visuals based on obtaining frequency data from sound, but I just couldn't get my mind around fft~, rfft~ etc. so I am going cheap using bandpass filters now which is not really what I wanted.  (Sidenote - does anyone know how other artists are accomplishing this?  I assumed they were using FFT)

I know this is a fairly advanced topic but I'd really love to figure out how to make it work.

Glad this came up!!
Kevin